Review this section to understand Oracle Database Appliance storage architecture and options and how to determine usable storage.
Topics:
Use Oracle Automatic Storage Management (Oracle ASM) or Oracle Automatic Storage Management Cluster File System (Oracle ACFS) for database files storage.
Database file systems are used exclusively for storing database files, and they include a DATA file system for database data files and a RECO file system for storing archive files and backups. Oracle Database Appliance supports Oracle ACFS and Oracle ASM database file storage. You determine the type of database storage when you create the database.
About Oracle ASM Database Storage
Use Oracle ASM with Oracle Database 12c release 1 (12.1.0.2).
With Oracle ASM, database datafiles are stored in DATA diskgroup. Redo and archive files are in RECO diskgroup.
About Oracle ACFS Database Storage
Use Oracle ACFS with Oracle Database 12c release 1 (12.1.0.2) or Oracle Database 11g release 2 (11.2.0.4).
With Oracle ACFS, an Oracle ACFS file system is created from DATA diskgroup for each database to store datafiles, and an Oracle ACFS file system is created from RECO diskgroup for redo and fast recovery area for all databases.
lsdg command to display mounted disk groups and their information for Oracle Database Appliance.Understand how database file storage is configured for Oracle Database Appliance X6-2.
Database file systems are used exclusively for storing database files, and they include a DATA file system for database data files and a RECO file system for storing archive files and backups. Oracle Database Appliance supports Oracle Automatic Storage Management Cluster File System (Oracle ACFS) or Oracle Automatic Storage Management (Oracle ASM) database file storage. You determine the type of database storage when you create the database.
About Oracle ASM Database Storage
Use Oracle ASM with Oracle Database 12c release 1 (12.1.0.2).
With Oracle ASM, database datafiles are stored in DATA diskgroup. Redo and archive files are in RECO diskgroup.
Reserved storage is the amount of Oracle Automatic Storage Management (Oracle ASM) storage required to maintain redundancy in the event of a disk failure. If you use the reserve storage capacity, then the system continues to run, and it is protected through Oracle ASM mirroring. However, in the event of a second disk failure, the system is then running in a non-protected and degraded mode. In this event, you must replace disks immediately.
See Also::
Oracle Automatic Storage Management Administrator's Guide for more information about Oracle ASM disk group capacity.
About Oracle ACFS Database Storage
Use Oracle ACFS with Oracle Database 12c release 1 (12.1.0.2) or Oracle Database 11g release 2 (11.2.0.4).
With Oracle ACFS, an Oracle ACFS file system is created from DATA diskgroup for each database to store datafiles, and an Oracle ACFS file system is created from RECO diskgroup for redo and fast recovery area for all databases.
Storage Configuration Options
External: Storage capacity is split between 80% for DATA and 20% for RECO.
Internal: Storage capacity is split between 40% for DATA and 60% for RECO.
Custom: Storage capacity is configurable from 10% to 90% for DATA and the remainder for RECO.
When you configure Oracle Database Appliance to use Custom data storage, the amount of usable storage is determined by the percentage configured for DATA.
You can run the lsdg command to determine the usable storage on the DATA disk group.
Review Oracle ASM Cluster file system (ACFS) mount points for Oracle Database Appliance.
If you select Oracle Automatic Storage Management (Oracle ASM) for database storage when you create a database, then an Oracle ASM Cluster file system (ACFS) is not created. All files are in an Oracle ASM diskgroup.
If you select Oracle ACFS for database storage, then each database has its own Oracle ACFS mount point:
DATA diskgroup: /u02/app/oracleuser/oradata/db_name
RECO diskgroup: /u03/app/oracleuser.
With Oracle ACFS, the following are created:
A 100G ACFS is created from +DATA diskgroup for each database. This Oracle ACFS automatically extends the space on demand.
A common Oracle ACFS with 25% of +RECO diskgroup is created with auto extension on. This file system is used for fast recovery area and redo logs for all databases.
Table B-1 Oracle ACFS Mount Points and Related Oracle ASM Disk Groups and Volume Information
| File System | Oracle ASM Disk Group | Oracle ASM Dynamic Volume | Mount Point |
|---|---|---|---|
|
DATA |
+DATA |
For example: |
For example: |
|
RECO |
+RECO |
|
This mount point is shared by all databases for For For redo logs, the path is: |
Example B-1 Oracle ACFS Storage Space
When the Oracle ACFS file systems are created, they do not initially consume all of the storage in the appliance. Space is preserved for additional repositories, or in some cases, database files stored directly in Oracle ASM. You can check for available storage space in your file systems by running the operating system command df -k as shown in the following example.
# df -k Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroupSys-LogVolRoot 30963708 14203568 15187276 49% / tmpfs 65952292 647800 65304492 1% /dev/shm /dev/sda1 495844 43872 426372 10% /boot /dev/mapper/VolGroupSys-LogVolOpt 61927420 18594420 40187272 32% /opt /dev/mapper/VolGroupSys-LogVolU01 103212320 49621560 48347880 51% /u01 /dev/asm/reco-62 76546048 1469676 75076372 2% /u03/app/oracle /dev/asm/datrdb2-268 104857600 3872368 100985232 4% /u02/app/oracle/oradata/rdb2 /dev/asm/datndb11-268 104857600 247160 104610440 1% /u02/app/oracle/oradata/ndb11 /dev/asm/datndb12-268 104857600 247160 104610440 1% /u02/app/oracle/oradata/ndb12
Use the Oracle Automatic Storage Management lsdg command to display mounted disk groups and their information for Oracle Database Appliance.
grid user.lsdg command.Example B-2 Determining Storage on the DATA Disk Group
ASMCMD [+] > lsdg data
State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB
MOUNTED NORMAL N 512 4096 4194304 12288 8835 1117 3859
(continued)
Offline_disks Voting_files Name
0 N DATA
Review the usable disk capacity available for Oracle Database Appliance X6-2S, X6-2M, and X6-2L and how capacity is derived.
Oracle Database Appliance X6-2S, X6-2M, and X6-2L use 3.2 TB raw NVMe flash Solid-State Drives. The usable data capacity in the following tables varies because it is derived by converting terabytes reported in decimal (based on 1 kilobyte equals 1,000 bytes) into terabytes reported in binary (based on 1 kilobyte equals 1,024 bytes) and splitting the usable capacity into Oracle Automatic Storage Management (Oracle ASM) disk groups.
In summary, each NVMe SSD usable storage is approximately 2.91TB. This is calculated by the storage usable capacity of the drive converted to TB. 3.2 TB divided by 1.0244= 2.91TB.
Usable Disk Capacity on Oracle Database Appliance X6-2S and X6-2M
The following table provides the approximate amount of usable space for the Oracle Database Appliance X6-2S and X6-2M.
Table B-2 Usable Disk Capacity on Oracle Database Appliance X6-2S and X6-2M
| Description | Sizing for X6-2S and X6-2M with 2 NVMe Drives | Sizing for X6-2S and X6-2M with 4 NVMe Drives |
|---|---|---|
| Number of NVMe Drives |
2 |
4 |
|
Total Usable Space |
5.8TB |
11.6TB |
|
Total Usable Normal (Double Mirror) Oracle ASM Redundancy |
2.9TB |
5.8TB |
|
DATA Disk Group (90% Usable) |
2.6TB |
5.2TB |
|
RECO Disk Group (10% Usable) |
0.3TB |
0.6TB |
|
Total Usable High (Triple Mirror) Oracle ASM Redundancy |
NA. Triple mirroring is not applicable for the X6-2S and X6-2M. |
3.9TB |
|
DATA Disk Group (90% usable) |
NA. Triple mirroring is not applicable for the X6-2S and X6-2M. |
3.5TB |
|
RECO Disk Group (10% usable) |
NA. Triple mirroring is not applicable for the X6-2S and X6-2M. |
0.4TB |
Usable Disk Capacity on Oracle Database Appliance X6-2L
Based on the calculations of the capacity of the storage drives and including the reserved space for redundancy, the following table reflects the approximate usable storage of the Oracle Database Appliance X6-2L.
Table B-3 Usable Storage on Oracle Database Appliance X6-2L
| Description | Sizing for X6-2L with 6 NVMe Drives | Sizing for X6-2L with 9 NVMe Drives |
|---|---|---|
|
Number of NVMe Drives |
6 |
9 |
|
Total Usable Space |
17.4TB |
26.1TB |
|
Reserved Space Normal Redundancy |
2.9TB |
2.9TB |
|
Total Usable Normal (Double Mirror) Oracle ASM Redundancy |
7.2TB |
11.6TB |
|
DATA Disk Group (90% usable) |
6.5TB |
10.4TB |
|
RECO Disk Group (10% usable) |
0.7TB |
1.2TB |
|
Reserved Space High Redundancy |
5.8TB |
5.8TB |
|
Total Usable High (Triple Mirror) Oracle ASM Redundancy |
3.8TB |
6.8TB |
|
DATA Disk Group (90% usable) |
3.4TB |
6.1TB |
|
RECO Disk Group (10% usable) |
0.4TB |
0.7TB |
The Reserved Space values represent the amount of storage required to maintain full redundancy in case of disk failure.
Oracle ASM Calculations
When Oracle ASM calculates usable Free Space, it determines the amount of space to reserve in the case of a disk failure. For Oracle Database Appliance X6-2S or X6-2M with 2 or 4 NVMe drives, this reserved space is not required. When you query Oracle ASM or Oracle Database Appliance commands to view the amount of storage available, the usable_File_MB value may report a negative number.
Table B-4 Oracle ASM Calculations
| Number of Drives | Redundancy | Total_MB | Free_MB | Req_mir_free_MB | Usable_file_MB | Name |
|---|---|---|---|---|---|---|
|
2 |
NORMAL |
4894016 |
4893372 |
0 |
1220644 |
RECO/ |
|
4 |
NORMAL |
1231176 |
1230996 |
610468 |
305150 |
RECO/ |
Note:
Note: 1TB = MB divided by 10242The following table describes how capacity terms are defined by Oracle ASM and Oracle Database Appliance.
Table B-5 Definition of Terminology
| Term | Oracle ASM Definition | Oracle Database Appliance Definition |
|---|---|---|
|
|
Size of the disk group in MB |
Total usable storage. For example, for 2 NVMe drives, total usable storage is 5.8TB. |
|
|
Free space in the disk group in MB, without regard to redundancy. |
Total usable storage after formatting to Oracle ASM disk groups. For example, for 2 NVMe drives, total usable storage is 5.8TB. |
|
|
Amount of space that must be available in the disk group to restore full redundancy after the worst failure that can be tolerated by the disk group. |
Total usable storage after formatting to Oracle ASM disk groups. For example, for 2 NVMe drives, total usable storage is 5.8TB. |
|
|
Amount of free space, adjusted for mirroring, that is available for new files. |
Total usable space taking into consideration the mirroring level. Oracle ASM also calculates the amount of space required. |